A Parametric Approach To Optimizing BGA Design For Reflow Reliability
Authors: A.Shirazi, H. Lu and A. Varvani-Farahani Company: Ryerson University Date Published: 5/4/2011
ICSR (Soldering and Reliability)
Abstract: Thermal warpage is a keen reliability concern for BGA (Ball Grid Array) and surface mounted PCBA (Printed Circuit Board Assembly). The authors previously proposed a hybrid method that correlates analytically modeled and directly measured warpage for a real package. While iteratively reaching the high correlation, the accuracy of the input material properties is simultaneously improved. An application of the model to a specific package is basically a model refining and verification process which ensures a high confidence level of the final modeling output such as the stresses/strains along the adhesive interfaces and the package warpage. Given that the output parameters are expressed as functions of temperature, geometric dimension and materials’ properties, the approach enables a quick, quantitative and full scale evaluation of the package’s performance. This paper presents an application example to illustrate how the method is executed in a package performance evaluation and prediction and how the evaluation facilitates the package design and manufacturing for reliability.
Key words: P-V Warpage, FCBGA Package, Residual Peel Stress, Residual Shear Stress, Warpage at peak reflow temperature